1. Field of the Invention
This invention generally relates to silicone rubber curing. It also relates to an anaerobic silicone rubber composition and more particularly, to a silicone rubber composition which can cure under anaerobic conditions at room temperature into silicone rubber which provides for bonding and sealing of such parts as screws, bolts, joints, and flanges.
2. Prior Art
Recently silicone rubber has found a spreading use in a new mode of application where molded silicone rubber is bonded to various substrates. As compared with synthetic rubber building gaskets, silicone rubber gaskets are improved in weatherability and flame retardancy and have low compression set, meeting the requirements as waterproof seals for buildings which require long-lasting reliability. Therefore, silicone rubber gaskets now encounter a rapidly increasing demand as waterproof seal in the building industry. These silicone rubber gaskets are used as waterproof seals by attaching them to metal curtain walls, concrete curtain walls, aluminum sashes, aerated lightweight concrete (ALC) panels and other members used as building exterior walls. The silicone rubber gaskets are bonded to exterior walls using such adhesives as silicone sealants.
The silicone sealants, however, are adhesive compositions which cure in the presence of moisture and thus require a substantial time until curing is complete. For instance, where silicone gaskets are attached to exterior walls with silicone sealants, the assembly must be allowed to stand for at least one day before a firm bond can be established between the silicone gaskets and the exterior walls. This means that exterior wall panels cannot be conveyed immediately after their manufacture, leading to low factory production and assembly efficiency.
Also, silicone rubber is used by applying it to screws, bolts, joints and flanges for fixedly securing or sealing them. For such use, a composition comprising a compound having at least one acryloyl or methacryloyl radical in a molecule and an anaerobic initiator is known from Japanese Patent Application Kokai (JP-A) No. 287115/1989. This composition, however, has the drawbacks of increased resin hardness, brittleness and slow curing due to the use of a compound having an acryloyl or methacryloyl radical.